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LNS. The new generation of SPAD Single Photon Avalanche Diodes arrays. Salvatore Tudisco. I Workshop on Photon Detection - Perugia 2007. - The Silicon Photomultiplier - Arrays for imaging. Microelectronics.
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LNS The new generation of SPAD Single Photon Avalanche Diodes arrays Salvatore Tudisco I Workshop on Photon Detection - Perugia 2007
- The Silicon Photomultiplier - Arrays for imaging Microelectronics The collaboration started in the 2004to realise single device and first array prototypes
High Boron (P+) concentration reduce the Breakdown voltage N- P+ P+ sinkers: reduce the contact resistance of the anode and provide a low resistance path to the avalanche current N- gettering region: impurities reduction Si <100> • Buried junctions p--p+ -n- : • P- high Breakdown voltage to prevent peripheral effects • P+ to reduce the series resistance substrate insulation integration of many elements E. Sciacca et al., IEEE Trans. on el. dev. 50 (2003) 4 E. Sciacca et al., IEEE Photonics Tech. Lett. 18 (2006) 15 SPAD p-n junction reversely biased above the breakdown voltage CMOS planar technology cathode 1 m SiO2
Psasive Quenching 100 k 50 SPAD Signal Rise time: 500 ps Fall time: 30 ns Recovery time: 1,5 s (increase with RL) Important for the applications (SiPM) Many elements integration simple quenching strategy
Photodetection Efficiency E.V. 10% E. Sciacca et al., IEEE Trans. on el. dev. 50 (2003) 4 M. Belluso et al. Mem. SAIT Suppl. 9 (2006) 430 SPAD PERPORMANCES • Photodetection Efficiency • Dark Counting Rate • Timing • Afterpulsing
d=20 mm SPAD PERPORMANCES • Photodetection Efficiency • Dark Counting Rate • Timing • Afterpulsing counter SPAD cooler S. Privitera et al. submited to NIMA
Single photon regime 120 ps Many photons regime TRIGGER Laser TDC 60 ps CH # SPAD1 CH # SPAD2 laser pulse 408 nm 60 ps FWHM Diffusion tail carrier diffusion in neutral layer delay to avalanche trigger S. Tudisco et al. Nuclear Physics B – proc. supl. 150(2006)317 Finocchiaro et al. IEEE Trans. on Nucl. Scie. 52(2005)3040 SPAD PERPORMANCES • Photodetection Efficiency • Dark Counting Rate • Timing • Afterpulsing
laser pulse 337 nm resolution 2 ns + dye for wave length-shift SPAD PERPORMANCES • Photodetection Efficiency • Dark Counting Rate • Timing • Afterpulsing Single photon regime Many photons regime
TRIGGER Dark event Multi Hits TDC CH # After-Pulses SPAD PERPORMANCES • Photodetection Efficiency • Dark Counting Rate • Timing • Afterpulsing Distribution of successive events to a primary avalanche uncorrelated dark counts S. Privitera et al. Submit. To NIMA
SPAD PERPORMANCES • Photodetection Efficiency • Dark Counting Rate • Timing • Afterpulsing Power law ? the two contributions in 10 s After the subtraction of the uncorrelated dark background S. Privitera et al. submit. to NIMA
Dark count rate distribution over 750 pixels (30 arrays) E. Sciacca IEEE Photonics Technology Letters 18 (13-16) (2006) 1633 20 m diameter, 160 m pitch SPAD ARRAY: 1st prototype 5x5 Anodes
A5 2mV/div A1 100 mV/div Electrical Cross-Talk 1st observation Induction; field fluctuations Common Substrate S. Privitera et al. submit. to NIMA SPAD ARRAY Optical Cross-Talk the avalanche multiplication process produce photons Isolation trench • 80 mm attenuation length • 10-5 photons per carrier crossing the junction
TRIGGER Pixel 5-1 Multi Hits TDC CH # Piexls 4-1, 4-2, 4-3, 3-1, 1-1 Two contributions: Prompt < 2 ns Delayed 2 ns 3 ms Probability: Prompt 10-5 Delayed 10-3 SPAD ARRAY Time and Spatial correlations START
Cross-Talk STOP Afterpulses 5-1 SPAD ARRAY Time and Spatial correlations • Cross-talk and Afterpulsing similar trend, different slop • No correlation with distances S. Privitera et al. Submit. to NIMA
Laser Pulse = 408 nm FWHM = 50 ps VA QDC channels QDC ADC Laser Pulse = 408 nm FWHM = 50 ps RL Oscilloscopio SPAD IOUT S. Privitera et al. submit. to NIMA A.Campisi et al. NIM A 571 (1-2) (2007)350 QDC or ADC channels SiPM Configuration
Event generator n° fired pixels parm. intensity Montecarlo Simulations Pixel ON Cross-talk generator parm. Probability Increasing the probability Cross-talk generator parm. dispersion Decreasing the dispersion Fill the spectrum
Conclusion • Single device performances (20m) • PDE: ~ 45% @ 550 nm • Dark counting rate: ~ 400 cps @ 25 °C, ~ 100 cps @ 15°C 20 • Timing: ~ 160 ps many-photons regime, ~ 300 ps single photon regime • Afterpulsing: ~ 10-3 pulses for primary avalanche • Limitations: • full recovery~ 1,5 s • 5X5 Array performances (20m) • Dark Counts uniformity: ~ 10% • Cross-Talk: prompt ~ 10-5 pulses for trigger • delayed ~ 10-3 pulses for trigger • No distance dependence • SiPM configuration: poor resolution • peak sensing (ADC) better then charge sensing (QDC) 2007 - 1st SiPM prototype (~ 5000 pixels), 1st array for imaging